The long term goal of this research is to develop noninvasive optical instruments and methods to monitor the metabolic state and assess the functional integrity of cold-stored and cold-perfused livers prior to transplant. This research is based on the working hypothesis that in hypothermically-stored livers, areas with dysfunctional oxidative metabolism can be detected noninvasively using spectrophotometric methods. During Phase I a computer-controlled imaging system was assembled and methods successfully developed to obtain and analyze cytochrome redox and NADH fluorescence images from cold-stored and cold- perfused rat livers. Comparison of normal and chemically-damaged livers yielded promising indicators of tissue damage which will be explored during Phase II. Phase II development will focus on preparing and testing the imaging system for use in clinical research. A subcontract with the Division of Transplantation at the University of Washington Medical Center will test a Phase II prototype at a research hospital. A noninvasive monitor of oxidative metabolism in livers awaiting transplant will have both clinical and research applications. The ability to detect liver dysfunction prior to transplantation will improve transplant planning, and the ability to establish liver viability will aid research directed towards increasing organ storage time.